Floating tool holder



5 M. BENJAMIN ET AL 2,778,647

FLOATING TOOL. HOLDER Filed March 26, 1954 INVENTORJ M/L 7'0/V L.BEN/AM/Nnuo .5 T WLEY 5. BENJAMIN A TfOE YEYJ.

2,778,647 i e e-"se a e. an

The present invention relates generallyiasiindicated to a floating toolholder and more particularly to a floating f tool holder of the generaltype disclosed in the Milton L. Benjamin et alLPatent Nos-2,547,518,granted April 3, 1951; 1

In the aforesaid patent construction, and in the present construction aswell, the fullefioating holder compensates for both angular and parallelmisalignment-betweenthe tool and the work spindlesof'machine tools, forexample. In other words, in both constructions, there isa ball-typejoint for universal angular adjustment of'the tool supporting member,and interposed between such ball-type joint and the tool supportingmember is, :ineifect, the elementsof an .Oldham coupling, the twoelements 'of which are non-rotatably interfitted with-eachother, andrespectively with the adjacent ball joint element, and with the;adjacent tool supporting 'member to accommodate parallel misalignmentalong angularly related axes.

A'principalobject of this invention is to provide a floating holderwhich employs ballfjoint trunnions'which are disposed radially, ratherthan axially as in the case-of the aforesaid patent. 1

Another object of this invention is toprovide metallic resilient meansfor efiecting pressure clamping to hold the parts of the assembly inadjusted position for self-aligning angular and transverse movement.

Another object of this invention is to provide a fu1lfloating holderwherein the aforesaid resilient means are located in the holderaccording to whether or not the holder as a whole is rotary ornon-rotary and also whether or not accurate control of depth of cut madein a workpiece is 'desired or necessary.

Other objects and advantages 'of the present invention will becomeapparent as the "following description proceeds.

To the accomplishment of the foregoing and related ends, the invention,then, comprises the features hereinafter fullydescribed and particularlypointed out in the claims, the following description and the annexeddrawings setting forth in detail certain illustrative embodiments of theinvention, these being indicative, however, of but a few of the variouswaysinwhich the principle of the invention may be'employed;

In said annexed drawings: 4

Fig. 1 is a longitudinalcross-section view of one em- .bodiment of thepresent invention, suchcross-section having been'taken'substantially'along the line 11', Fig. 2;

Fig. 2 is a transverse cross-section taken substantially along the line22, Fig. 1; and

Fig. 3 is a fragmentary longitudinal cross-section view of a modifiedform of holder.

Referring now more particularly to the drawing and first to the form ofthe holder illustrated in Figs. 1 and 2, the same is shown as comprisinga body or housing 1 which is provided with an elongated shank 2 adaptedto be secured to the tool spindle of a metal working machine.

Said housing 1 is further provided with an exteriorly threaded portion 3within which is formed a conical seat 42 At diametrically opposite sidesof said portion 3, ad'- jacentsaid. seat 4 and extending radially; area-pair of cylindrical pins 5 press-fitted or otherwise securedin place.As s hown, said pins 5 extendradially inward to'point's adjacent thebase of said conical seat 4. ski-Y 1 1 Within tubular portion 3 ofsaid-housing '1 is a series of three members 6, 7, and 8 respectivelyhaving'a universallytiltable, driving connection with said housingil andtransversely movable, driving connections with each otheralonggangularly disposed paths.

:The first of said series of members is a drive ring fi I which isformedwith a spherical protuberance 9 adapted to makejlinecontactengagementxwith the conical seat 4 ah'dforrned with a radiallyextending flange 103 Said flange' '10 is'formed with. fourequally"spaced-peripheral notches '11-; two of which' notches areadapted tofitrather closely over rthe sinwardly I projecting ends :ofsaid pins 5 for: securing rapo'sitive driving engagement between housing:1 and .ring 6, while allowing' universal tilting offthe latterwhile-engaged with seat-4. -The center'line of' said 'pins 5preferablycoincides with the center of the-spheric'al protuberance 9. Inthis way, the notches 11 may reasonably clos'ely'embrace theends of saidpins 5 and yet said ring-6 may be universally'tilted. I 1 -'=The secondor intermediateone of'said series of-member's is a 'ball retaine'r ring7 carrying a plurality of circularly arranged balls 14 therein, eachof'diameter greater than the thickness of said'ring 7,'the balls 14being-held inplace'in said ring 7 as by peenin'g over of the edges ofthe openings iri' whicli the "balls are fitted. T \r 1 As sh'own, saidretainer ring7 is forme'd with diametricallyfopposed axially extendinglugs l5iwhich are adapted to fit, with some clearance, within theotherpair of notches 11 in said drive ring 6 to secure positive drivingof ring 7 through ring 6 and adjustment of said ring 7 along a pathtransverse to its axis, that is','in a direction parallel to the opposedlugs-15. Said ring 7 is further formed with an= otherpairofjsimilar-diametricallyopposed lugs'16 which extend axiallyin'the'opposite direction from and out ofphasewith said lugs 15'. Thethird or last oneof s'aid' series of members is a floating 'holdershankSof tubular form threaded at one end "asshown and formed with'a flange 17at the other end, such flangehaving a pair of diametrically opposednotcheslS adapted to' fit over said 1ugs16 of said ballretaine'r' ring7, whereby said holder shank 8 may also be adjusted transversely of itsaxis but along a path at right anglesto th'e path of transverseadjustment of said ballretainer ring 7. The fit of the notches 18 overthe lugs 16 provides a driving connection between said ball-retainerring 7'and said holder shank 8. It is to be understood that the holdershank 8 may be ofany of'thetypes shown in Figs. 1, 3, and 4 of theaforesaidBenjamin et aL'Patent No. '2,'547,5l8. The holder shank 8, asherein shown, is formed to accommodate a contractible collet, and forsuch purpose said shank 8 is provided with a bore having co-axial andaxially spaced conical seats 19 and 20 comparable with the seats formediii the'like shank member disclosed in the aforesaid patent and, aswell, in the Milton 'L; Benjamin et a1. Patent No. 2358300 datedSeptember 19, 1944. i i A contractible collet 21 is fitted into the boreof said shank member 8, said collet having conical faces 22 and 23respectively engageable with the conical seats 19 and 20; and, asapparent, axial movement of said collet 21 into said holder shank 8 willeifect contraction of said collet so as to grip a tool or the liketherein. The collet 21 is moved endwise into the holder shank 8 as bymeans of the nose piece 24 which is threaded onto said shank 8 and bearson the outer end of said collet through the intermediary of a nose ring25.

The series of members 6, 7, and 8 are clamped in the housing 1 by meansof a counterbored ring 26 providing a shoulder which bears against theflange 17 of said holder shank 8, a clamp nut 27 being threaded ontosaid housing 1 and having an inturned flange 28 engaging the outer endof said ring 26. As shown, the bore through said ring 26 is slightlylarger than the diameter of the holder shank 8 so that the latter may beangnlarly or eccentrically positioned therein.

Interposed between said drive ring 6 and housing 1 are a series of coilsprings 29, and of course, instead of coil springs, a wavey springwasher or the like may be employed which bears against the flange 10 ofsaid ring.

In the use of this form of the full floating holder, the shank ofareamer R or like tool is positioned within the collet 21 and the nosepiece 24 is tightened to grip the tool.

The nut 27 is tightened to cause the spherical protuberance 9 to engagethe seat 4 and then is backed off a slight amount, such as a quarterturn, and locked in such position as by means of the check nut 30. Inthis condition of the parts, there is a few thousandths inch clearancebetween the spherical protuberance 9 and its conical seat 4 whereby thetool R gripped by the collet 21 may readily align itself with the holein the workpiece which is being reamed and thus may partake of angularand also parallel movement for such purpose.

However, because the spherical protuberance 9 and seat 4 are not inengagement at this time, this construction is not preferred in instanceswhere accurate control of depth of the reamer R or other tool into thework is required. This holder is better employedin non-rotating userather than rotating use, because initial angular misalignment mightincrease owing to rotation, whereupon difliculty would be encountered inthe initial entry of the end of the tool R into the work. Of course,parallel misalignment is readily accommodated by the chamfer at the endof the tool R whether the holder is rotated or not.

The modified form of full-floating holder as illustrated in Fig. 3 is ofsubstantially the same construction as that already described, andtherefore repetition is not necessary. Instead of providing springs '29vbetween the housing 1 and the drive ring 6, the pressure ring 31 is ofresilient construction and is here shown'as made up of two telescopedrings 32 and 34 having a plurality of springs 35 therebetween, one ring32 having a flange 36 engaged by the inturned flange of the nut 27, andthe other ring 34 being counterbored to provide a shoulder which bearsagainst the flange 17. of said holder shank 8. As before indicated,instead of a plurality of coil springs 35, a single spring may beemployed or a wavey spring washer or the like.

Thus, when the nut 27 is tightened, the series of members 6, 7, and 8are resiliently clamped together, the protuberance 9 being engaged withthe conical seat 4 so that, even if this form of full-floating holder isemployed in a rotating use, the angular misalignment is not increasedowing to such rotation; and, therefore, the chamfered end of a tool Rwill readily enter a bore in the work as the holder is rotated and fedaxially with respect to the work. During such feeding axially the toolfollows the bore of the work by reason of the Oldham type coupling andthe ball joint.

As a further feature of this invention, the springs 29 or 35, as thecase may be, have slightly enlarged ends, thus necessitating threadingof the same into place into 4 their sockets whereby they will not fallout upon disassembly of the holder.

Other modes of applying the principle of the invention may be employed,change being made as regards the details described, provided thefeatures stated in any of the following claims, or the equivalent ofsuch, be employed.

'vVe therefore particularly point out and distinctly claim as ourinvention:

1. In a floating holder for tools and the like, the combination of ahousing, a tool gripping assembly having a universally tiltable andtransversely movable positive driving connection with said housing, saidassembly comprising a plurality of adjacent members having suchtransversely movable positive driving connection with each other, one ofsaid members and said housing having diametrically opposed, interfittingradial slots and coaxial, radial pins to provide such universallytiltable positive drive connection, and means for clamping said memberstogether in said housing.

2. In a floating holder for tools and the like, the combination of ahousing, a tool gripping assembly having a universally tiltable andtransversely movable positivedriving connection with said housing, saidassembly comprising a plurality of adjacent members having suchtransversely movable .positive driving connection with each other, oneof said members and said housing having diametrically opposed,interfitting radial slots and coaxial, radial pins to provide suchuniversally tiltable positive drive connection, and means forresiliently clamping said members together in said housing whereby atool gripped by said assembly may shift to accommodate parallel andangular misalignment thereof with a workpiece.

3. The holder of claim 2 wherein said one member has a spherical endportion engaged in said housing and said means for resiliently clampingsaid members together in said housing acts through another of saidmembers to urge said one member into engagement with said housing.

4-. The holder of claim 2 wherein said means for resiliently clampingsaid members together includes a nut threadedly engaged with saidhousing to engage an adjacentone of said members, and resilient meansbetween said one member and said housing resiliently permitting suchuniversal tilting.

5. In a floating holder for tools and the Ilike, the combination of ahousing, a tool gripping assembly having a universally tiltable andtransversely movable positive driving connection with said housing, saidassembly comprising a plurality of adjacent members having suchtransversely movable positive driving connection with each other, one ofsaid members and said housing having a pin I and slot universal positivedriving connection with each References Cited in the file of this patentUNITED STATES PATENTS 119,173 Philippi Sept. 19, 1871 2,547,518 Benjaminet al Apr. 3, 1951 2,675,242 Olson Apr. 13, 1954

